Temporary lighting applications, such theatrical or event lighting, often involve the use of temporary power distribution systems in order to distribute power from a central location to where it is needed. These distribution systems often feature a single set of high-current 3-phase AC input connections, such as, for example: 400 A, 120/208 VAC, 3 Phase, and many low-power, e.g. 20 A, single phase output connections. Often, multiple individual circuits are bundled together into a single multi-cable configuration in order facilitate the cabling of multiple parallel connections.
FIG. 1 illustrates an example of a power distribution rack 100 having a plurality of power output connectors 110. FIG. 2 illustrates an example of a 6-circuit multi-cable 200 which may be employed with power distribution rack 100.
Intelligently-controllable lighting equipment is commonly controlled by the industry-standard DMX512-A control protocol or by one of several Ethernet protocols. For most types of equipment and applications, power and data wires must be run separately. Compared to power cables, data cables tend to be relatively delicate and must be handled with greater care.
The computer networking industry has developed ways to transmit Ethernet data over AC power lines. Such power line communication (PLC) works reasonably well for residential computer networking.
While conventional PLC technologies offer robust performance allowing PLC data to propagate through an electrical panel from one circuit to another, this does not always happen reliably and depends on the size and complexity of the electrical system, the devices connected to the system, the routing of the wiring, and environmental conditions.
The PLC-based approach has recently been deployed to enable digitally controllable LED lighting solutions using existing electrical infrastructures for small and medium lighting networks, as described at http://colorkinetics.com/IntelliPower/, incorporated herein by reference. However, for control of larger lighting systems, particularly those set up temporarily for entertainment, theatrical, and event lighting applications, special care must be taken to ensure functional/reliable operation and scalability, because a single PLC network is limited in bandwidth and may not have enough capacity to reliably control a large lighting system.
Further, the size and complexity of power distribution systems varies greatly from application to application. A single PLC transmitter may not have adequate signal strength to reach every PLC node in many systems. PLC transmitters are also limited in the number of nodes they can communicate with and the bandwidth they can support.
PLC data or signals are capable of coupling or “jumping” from one AC circuit to another [electrically isolated] AC circuit when cables are run in close proximity to each other (such as would be the case in multi-circuit multi-cables or any cables that are routed in bundles). This could result in interference, unpredictable performance, and could make it difficult to identify the locations of different PLC enabled devices in the system (which would be problematic for system configuration).
When PLC enabled devices are installed in a new application, they will likely be configured with an unknown PLC Network ID. For security reasons, it may not be possible to change this network ID remotely without knowing what it is.
Much of the equipment in the entertainment/event lighting industry is owned by rental companies. This equipment is moved from job to job and typically must be re-configured for each application. In this context, it is important that the power distribution can be set up and taken down quickly, and that circuits operate with a very high reliability. Furthermore, these companies have a substantial investment in existing cables such as 6-circuit multi-cable 200 shown in FIG. 2, and it would be desirable to employ these same cables in a temporary lighting and multimedia installations which employ PLC enabled devices.
Thus, it would be desirable to enable expanding and configuring a PLC control system, particularly for temporary lighting and multimedia installations, in a way that increases bandwidth, reduces costs, and improves ease of installation, reliability and security.